FYI FORD MustangSteve's Ford Mustang Forum / Oil pressure gauge plus LED lights???

**Posted by RTM** 10/13/2024 10:11 AM

I have an extra Red LED light and was thinking of tiring it into the oil pressure gauge but I'm not sure at what point the KED would go off if I lost oil pressure. I suspect it would be zero oil pressure before the LED turned off.

Not sure if it's worth the extra work to add it or not. I think this was mentioned in one of my older posts.

**Posted by Texas!** 10/14/2024 4:55 AM

You will need another sending unit for the red light, one from a '65 Mustang that had an oil pressure warning light instead of a gauge. The only problem with that is that the red light doesn't illuminate until the pressure has dropped to about 5 psi which may be too late.to prevent damage. Perhaps there is an aftermarket sending unit that closes the switch at about 20 psi which would give you a few seconds to react.

**Posted by BobE** 10/14/2024 7:23 AM

Texas! wrote:
You will need another sending unit for the red light, one from a '65 Mustang that had an oil pressure warning light instead of a gauge. The only problem with that is that the red light doesn't illuminate until the pressure has dropped to about 5 psi which may be too late.to prevent damage. Perhaps there is an aftermarket sending unit that closes the switch at about 20 psi which would give you a few seconds to react.

I agree, the OEM pressure switch is so low that damage has likely already occurred. A switch with a 20psi rating would certainly be better choice, IMO.
From my perspective, for a non-race car, when was the last time you heard of a street driven car losing oil pressure?

**Posted by RTM** 10/14/2024 9:42 AM

Was just talking to my buddy in Ohio about this. He basically has said the same thing. He does recall of a car back in the day that had a feature with the light and a gauge but couldn't recall the specifics of how it was setup. He did say he's going to give it some thought and we also discussed being able to turn off the light at 20 psi. I'm sure someone out there can figure that out but it's not me. Lol

**Posted by John Ha** 10/14/2024 1:52 PM

Although the oil light sender does have the shortcomings mentioned, the light does tend to attract more attention than a gauge reading low (which could be unnoticed for a long-enough time for major damage to occur). It seems to me that it might be worth having if only for that reason. JMHO, of course.

**Posted by Texas!** 10/14/2024 6:43 PM

This may be what you're looking for. The description is not very informative.
https://www.amazon.com/Allstar-ALL99059-Pressure-Switch-Thread/dp/B006K8WG44

It is what you're looking for. A better decription.
https://allstarperformance.com/pressure-switch-20-psi-all99059/

Last edited by Texas! (10/14/2024 6:51 PM)

**Posted by rpm** 10/14/2024 8:18 PM

John Ha wrote:
Although the oil light sender does have the shortcomings mentioned, the light does tend to attract more attention than a gauge reading low (which could be unnoticed for a long-enough time for major damage to occur). It seems to me that it might be worth having if only for that reason. JMHO, of course.

This is why I installed one.

**Posted by RTM** 10/15/2024 7:05 AM

Texas! wrote:
This may be what you're looking for. The description is not very informative.
https://www.amazon.com/Allstar-ALL99059-Pressure-Switch-Thread/dp/B006K8WG44

It is what you're looking for. A better decription.
https://allstarperformance.com/pressure-switch-20-psi-all99059/

I just ordered that switch. I really like the idea of a red light coming on if I drop below 20psi. I'll place the red LED right in the center of the speedometer and Tachometer gauges.

I also found this extension that has dual ports. I ordered it as well.

**Posted by BobE** 10/15/2024 7:55 AM

FYI - the oil pressure port in the engine block is 1/4" NPT threads. The switch is 1/8" NPT, that extension appears maybe to have both, and w/o the dual ports it looks very similar to the OEM extension Ford used for the oil pressure sensors.

**Posted by RTM** 10/15/2024 8:20 AM

BobE wrote:
FYI - the oil pressure port in the engine block is 1/4" NPT threads. The switch is 1/8" NPT, that extension appears maybe to have both, and w/o the dual ports it looks very similar to the OEM extension Ford used for the oil pressure sensors.

I was going to just drill and tap my current extension but saw this when I did a quick search. Figured I would give this a try. Worse case is I may have to put a small extension in the 1/8 port to raise the pressure switch up a little to clear the oil pressure switch. The oil switch is pretty large in diameter.

**Posted by rpm** 10/15/2024 6:29 PM

I have an oil idiot light sender and a gauge sender on the stock extension. I had to put the smaller idiot light sender on the end due to packaging issue with the manual fuel pump with filter, and the alternator in that space. I drilled and tapped for the gauge sender in the only area it would fit.

**Posted by RTM** 10/16/2024 6:28 AM

I don't have the extension installed here but it's a tight fit. The autometer oil sensor is pretty big. I'll snap a picture of it tonight when I get home. I have all the common NPT taps in my tool box.

**Posted by BobE** 10/16/2024 7:20 AM

Note that the 1/8" and 1/4" NPT are normal thread size used in the plumbing world. Pipe nipples of various lengths, elbows, tees etc., are available at Home Depot, Lowes, Ace Hardware, etc. (but may not look as nice)
I wouldn't use a plastic line to feed the oil gauge. 1/8" copper tubing would be a better choice IMO. (Especially that close to the exhaust header)
Just saying.

**Posted by RTM** 10/16/2024 8:16 AM

BobE wrote:
Note that the 1/8" and 1/4" NPT are normal thread size used in the plumbing world. Pipe nipples of various lengths, elbows, tees etc., are available at Home Depot, Lowes, Ace Hardware, etc. (but may not look as nice)
I wouldn't use a plastic line to feed the oil gauge. 1/8" copper tubing would be a better choice IMO. (Especially that close to the exhaust header)
Just saying.

The plastic oil pressure line was only used for the test start I did on the engine cart. It's not a permanent thing and has since been removed. The autometer oil pressure gauge is electronic.

I was already thinking I may have to raise the pressure switch I want to add up a little to get a better fit. Once it's painted black no one will ever notice I used plumbing pipe from HD. Lol.

**Posted by Rudi** 10/16/2024 8:54 AM

Copper line will work harden and crack if subjected to vibration.
I unfortunately found that out many years ago when the oil pressure gauge connection in my home built sprung a leak 3000’ over Chicago flying home from Oshkosh.

**Posted by rpm** 10/16/2024 11:04 AM

Rudi wrote:
Copper line will work harden and crack if subjected to vibration.
I unfortunately found that out many years ago when the oil pressure gauge connection in my home built sprung a leak 3000’ over Chicago flying home from Oshkosh.

C'mon Paul Harvey, tell us the rest of the story.

**Posted by Rudi** 10/16/2024 2:11 PM

rpm wrote:
Rudi wrote:
Copper line will work harden and crack if subjected to vibration.
I unfortunately found that out many years ago when the oil pressure gauge connection in my home built sprung a leak 3000’ over Chicago flying home from Oshkosh.

C'mon Paul Harvey, tell us the rest of the story.

Ok Bob here ya go!
The oil pressure gauge on the instrument panel was right over my right leg and luckily the 1/8” copper line was not cracked all the way through but it had a steady drip of hot oil, not very pleasant.

On the way home my route was following the west shore of Lake Michigan , too far away from Ohare , probably not an option anyway, and I had just passed Meigs Field and rather than turning back I header on to Michigan city air field just past Gary Indiana about 15 minutes away. Adding to pucker factor the C85 Continental started to miss on one cylinder just before final. I shut it down as soon as I touched down. I think of lack of oil and a questionable lifter caused the miss.

I found out the FBO was closed but was able to scrounge a pair a pair of vice grips to disconnect the fitting at the gauge and fold over the copper line and crimp it.
One of the guys t the airport found some cans oil and it took a little over a quart to fill it back up.
When I restarted the engine the miss was gone but it was sure on my mind for the rest of the trip home without an oil pressure gauge.
I replaced the copper line with one that was SS braided ,Teflon lined .
The joys of sport aviation!

**Posted by BobE** 10/17/2024 7:22 AM

Rudi - Wow, glad that trip ended safely for you.

**Posted by RTM** 10/17/2024 9:21 AM

That sure would be something that would cause me to have a panic attack. Rudi hiw old was that copper line?

**Posted by Rudi** 10/17/2024 3:10 PM

That sure would be something that would cause me to have a panic attack. Rudi hiw old was that copper line

Yeah it was a major pucker episode, almost as bad as the 500 ‘ AGL engine failure on take off a few hours after the first flight.
The copper line failure happened about a year after the first flight.
Less than 25 hours of flying time , new when installed. There were anti fatigue loops at each end as well.
The crack was right at the compression nut at the back of the gauge.

Last edited by Rudi (10/17/2024 3:11 PM)

**Posted by Nos681** 10/18/2024 5:43 AM

Another option would be to use the Ni-Copper or steel brake lines.

**Posted by Ron68** 10/18/2024 4:05 PM

Rudi wrote:
Copper line will work harden and crack if subjected to vibration.
I unfortunately found that out many years ago when the oil pressure gauge connection in my home built sprung a leak 3000’ over Chicago flying home from Oshkosh.

Years ago I was in a very old Cessna 310 in the front passenger seat flying over the Cascade mountain range - at night - in Washington when I felt something warm and wet on my left foot. The right hand engine oil pressure gauge was leaking oil down the back side of the instrument panel. Old style direct reading gauge with a copper tube going to the back side. Had some rags, so I wiped up what I could and put the rags on the top of my foot. We made it to Moses Lake in eastern Washington finally and landed. We checked the oil quantity and added a half quart, but we also found the exhaust stack for #4 cylinder had broken off. The owner called his partner to fly us in another stack from Seattle. It was about 2:30 am when he landed with the part and the owner's mechanic. I had accompanied the owner to change out a magneto on a Beech Queen Air so it could be repossessed, but that job went to Hell. I told the owner that I was done and hitched a ride back to Seattle on his partner's 182. General Aviation..................

**Posted by RTM** 10/19/2024 5:45 PM

I e always wanted to learn how to fly, not so sure now. Lol

I did mount the red LED between the tach and speedometer. I tested the pressure switch and it's grounded with no pressure and once I put pressure the gauge it opened the circuit.

**Posted by RTM** 10/21/2024 5:42 PM

The extension arrived today so I had to install it. The extension is a little longer than the one I had on there. I had to remove the hydro boost return line from the back of the pump in order to thread the oil pressure gauge in. Tight fit but both the switch and gauge are in.